Dementia praecox

The term dementia praecox was first used by German psychiatrist Heinrich Schüle in 1880.

It was also used in 1891 by Arnold Pick (1851–1924), a professor of psychiatry at Charles University in Prague. In a brief clinical report, he described a person with a psychotic disorder resembling "hebephrenia" (an adolescent-onset psychotic condition).

German psychiatrist Emil Kraepelin (1856–1926) popularised the term dementia praecox in his first detailed textbook descriptions of a condition that eventually became a different disease concept later relabeled as schizophrenia. Kraepelin reduced the complex psychiatric taxonomies of the nineteenth century by dividing them into two classes: manic-depressive psychosis and dementia praecox. This division, commonly referred to as the Kraepelinian dichotomy, had a fundamental impact on twentieth-century psychiatry, though it has also been questioned.

The primary disturbance in dementia praecox was seen to be a disruption in cognitive or mental functioning in attention, memory, and goal-directed behaviour. Kraepelin contrasted this with manic-depressive psychosis, now termed bipolar disorder, and also with other forms of mood disorder, including major depressive disorder. Eventually, he concluded it was not possible to distinguish his categories on the basis of cross-sectional symptoms.

Kraepelin viewed dementia praecox as a progressively deteriorating disease from which no one recovered. However, by 1913, and more explicitly by 1920, Kraepelin admitted that while there may be a residual cognitive defect in most cases, the prognosis was not as uniformly dire as he had stated in the 1890s. Still, he regarded it as a specific disease concept that implied incurable, inexplicable madness.

History

The history of dementia praecox is really that of psychiatry as a whole.

— Adolf Meyer

First use of the term

Dementia is an ancient term which has been in use since at least the time of Lucretius in 50 BC where it meant "being out of one's mind". Until the seventeenth century, dementia referred to states of cognitive and behavioural deterioration leading to psychosocial incompetence. This condition could be innate or acquired, and the concept had no reference to a necessarily irreversible condition. It is the concept in this popular notion of psychosocial incapacity that forms the basis for the idea of legal incapacity. By the eighteenth century, at the period when the term entered into European medical discourse, clinical concepts were added to the vernacular understanding such that dementia was now associated with intellectual deficits arising from any cause and at any age. By the end of the nineteenth century, the modern 'cognitive paradigm' of dementia was taking root. This holds that dementia is understood in terms of criteria relating to aetiology, age and course which excludes former members of the family of the demented such as adults with acquired head trauma or children with cognitive deficits. Moreover, it was now understood as an irreversible condition and a particular emphasis was placed on memory loss in regard to the deterioration of intellectual functions.

The term démence précoce was used in passing to describe the characteristics of a subset of young mental patients by the French physician Bénédict Augustin Morel in 1852 in the first volume of his Études cliniques. and the term is used more frequently in his textbook Traité des maladies mentales which was published in 1860. Morel, whose name will be forever associated with religiously inspired concept of degeneration theory in psychiatry, used the term in a descriptive sense and not to define a specific and novel diagnostic category. It was applied as a means of setting apart a group of young men and women with "stupor". As such their condition was characterised by a certain torpor, enervation, and disorder of the will and was related to the diagnostic category of melancholia. He did not conceptualise their state as irreversible and thus his use of the term dementia was equivalent to that formed in the eighteenth century as outlined above.

While some have sought to interpret, if in a qualified fashion, the use by Morel of the term démence précoce as amounting to the discovery of schizophrenia, others have argued convincingly that Morel's descriptive use of the term should not be considered in any sense as a precursor to Kraepelin's dementia praecox disease concept. This is due to the fact that their concepts of dementia differed significantly from each other, with Kraepelin employing the more modern sense of the word and that Morel was not describing a diagnostic category. Indeed, until the advent of Pick and Kraepelin, Morel's term had faded from use and there is little evidence to suggest that either Pick or indeed Kraepelin were even aware of Morel's use of the term until long after they had published their own disease concepts bearing the same name. As Eugène Minkowski stated, "An abyss separates Morel's démence précoce from that of Kraepelin."

Morel described several psychotic disorders that ended in dementia, and as a result he may be regarded as the first alienist or psychiatrist to develop a diagnostic system based on presumed outcome rather than on the current presentation of signs and symptoms. Morel, however, did not conduct any long-term or quantitative research on the course and outcome of dementia praecox (Kraepelin would be the first in history to do that) so this prognosis was based on speculation. It is impossible to discern whether the condition briefly described by Morel was equivalent to the disorder later called dementia praecox by Pick and Kraepelin.

Time component

Psychiatric nosology in the nineteenth-century was chaotic and characterised by a conflicting mosaic of contradictory systems. Psychiatric disease categories were based upon short-term and cross-sectional observations of patients from which were derived the putative characteristic signs and symptoms of a given disease concept. The dominant psychiatric paradigms which gave a semblance of order to this fragmentary picture were Morelian degeneration theory and the concept of "unitary psychosis" (Einheitspsychose). This latter notion, derived from the Belgian psychiatrist Joseph Guislain (1797–1860), held that the variety of symptoms attributed to mental illness were manifestations of a single underlying disease process. While these approaches had a diachronic aspect they lacked a conception of mental illness that encompassed a coherent notion of change over time in terms of the natural course of the illness and based upon an empirical observation of changing symptomatology.

In 1863, the Danzig-based psychiatrist Karl Ludwig Kahlbaum (1828–1899) published his text on psychiatric nosology Die Gruppierung der psychischen Krankheiten (The Classification of Psychiatric Diseases). Although with the passage of time this work would prove profoundly influential, when it was published it was almost completely ignored by German academia despite the sophisticated and intelligent disease classification system which it proposed. In this book Kahlbaum categorized certain typical forms of psychosis (vesania typica) as a single coherent type based upon their shared progressive nature which betrayed, he argued, an ongoing degenerative disease process. For Kahlbaum the disease process of vesania typica was distinguished by the passage of the patient through clearly defined disease phases: a melancholic stage; a manic stage; a confusional stage; and finally a demented stage.

In 1866, Kahlbaum became the director of a private psychiatric clinic in Görlitz (Prussia, today Saxony, a small town near Dresden). He was accompanied by his younger assistant, Ewald Hecker (1843–1909), and during a ten-year collaboration they conducted a series of research studies on young psychotic patients that would become a major influence on the development of modern psychiatry.

Together Kahlbaum and Hecker were the first to describe and name such syndromes as dysthymia, cyclothymia, paranoia, catatonia, and hebephrenia. Perhaps their most lasting contribution to psychiatry was the introduction of the "clinical method" from medicine to the study of mental diseases, a method which is now known as psychopathology.

When the element of time was added to the concept of diagnosis, a diagnosis became more than just a description of a collection of symptoms: diagnosis now also defined by prognosis (course and outcome). An additional feature of the clinical method was that the characteristic symptoms that define syndromes should be described without any prior assumption of brain pathology (although such links would be made later as scientific knowledge progressed). Karl Kahlbaum made an appeal for the adoption of the clinical method in psychiatry in his 1874 book on catatonia. Without Kahlbaum and Hecker there would be no dementia praecox.

Upon his appointment to a full professorship in psychiatry at the University of Dorpat (now Tartu, Estonia) in 1886, Kraepelin gave an inaugural address to the faculty outlining his research programme for the years ahead. Attacking the "brain mythology" of Meynert and the positions of Griesinger and Gudden, Kraepelin advocated that the ideas of Kahlbaum, who was then a marginal and little known figure in psychiatry, should be followed. Therefore, he argued, a research programme into the nature of psychiatric illness should look at a large number of patients over time to discover the course which mental disease could take. It has also been suggested that Kraepelin's decision to accept the Dorpat post was informed by the fact that there he could hope to gain experience with chronic patients and this, it was presumed, would facilitate the longitudinal study of mental illness.

Quantitative component

Understanding that objective diagnostic methods must be based on scientific practice, Kraepelin had been conducting psychological and drug experiments on patients and normal subjects for some time when, in 1891, he left Dorpat and took up a position as professor and director of the psychiatric clinic at Heidelberg University. There he established a research program based on Kahlbaum's proposal for a more exact qualitative clinical approach, and his own innovation: a quantitative approach involving meticulous collection of data over time on each new patient admitted to the clinic (rather than only the interesting cases, as had been the habit until then).

Kraepelin believed that by thoroughly describing all of the clinic's new patients on index cards, which he had been using since 1887, researcher bias could be eliminated from the investigation process. He described the method in his posthumously published memoir:

... after the first thorough examination of a new patient, each of us had to throw in a note [in a "diagnosis box"] with his diagnosis written on it. After a while, the notes were taken out of the box, the diagnoses were listed, and the case was closed, the final interpretation of the disease was added to the original diagnosis. In this way, we were able to see what kind of mistakes had been made and were able to follow-up the reasons for the wrong original diagnosis.

The fourth edition of his textbook, Psychiatrie, published in 1893, two years after his arrival at Heidelberg, contained some impressions of the patterns Kraepelin had begun to find in his index cards. Prognosis (course and outcome) began to feature alongside signs and symptoms in the description of syndromes, and he added a class of psychotic disorders designated "psychic degenerative processes", three of which were borrowed from Kahlbaum and Hecker: dementia paranoides (a degenerative type of Kahlbaum's paranoia, with sudden onset), catatonia (per Kahlbaum, 1874) and dementia praecox, (Hecker's hebephrenia of 1871). Kraepelin continued to equate dementia praecox with hebephrenia for the next six years.

In the March 1896 fifth edition of Psychiatrie, Kraepelin expressed confidence that his clinical method, involving analysis of both qualitative and quantitative data derived from long term observation of patients, would produce reliable diagnoses including prognosis:

What convinced me of the superiority of the clinical method of diagnosis (followed here) over the traditional one, was the certainty with which we could predict (in conjunction with our new concept of disease) the future course of events. Thanks to it the student can now find his way more easily in the difficult subject of psychiatry.

In this edition dementia praecox is still essentially hebephrenia, and it, dementia paranoides and catatonia are described as distinct psychotic disorders among the "metabolic disorders leading to dementia".